Film cartridge guide assembly

ABSTRACT

In a movie projector designed to receive and operate with a film cartridge, where the film cartridge housing is constructed with guiding surfaces that cooperate with complementary guide surfaces in the cartridge receptacle of the movie projector to cause the cartridge to follow a predetermined path when inserted or removed from the receptacle in order that the film cartridge will always be brought into a proper operating relationship with the various operating components of the movie projector.

United States Patent Zahradnik [54] FILM CARTRIDGE GUIDE ASSEMBLY [72]Inventor: George J. Zlhlfldllil, Wheaten, Ill.

[73] Assigneez' A. B. Dick-Company, Chicago, Ill.

22 Filed: June 19, 1970 21 Appl.'No.: 47,660

[52] US. Cl ..226/89, 352/72 [51] Int. Cl. G03b 1/56 [58] Field ofSearch..352/72, 74-78;

[56] References Cited UNITED STATES-PATENTS 2,504,317 4/1950 Frankel;..352/74 1151 3,656,675 1451 Apr. 18, 1972 1/1968 Easterly ..352/721/1970 Hickl ..'....352/72 Primary Examiner-Richard A. SchacherAttomey-Johnson, Dienner, Emrich, Verbeck & Wagner [57] I ABSTRACT in amovie projector designed to receive and operate with a film cartridge,where the film cartridge housing is constructed with guiding surfacesthat cooperate with complementary guide surfaces in the cartridgereceptacle of the movie projector to cause the cartridge to follow apredetermined path when inserted or removed from the receptacle in orderthat the film cartridge will always be brought into a proper operatingrelationship with the various operating components of the movieprojector. I

12 Claims, 9 Drawing Figures PATENTEDAPR 18 I972 6 56 67 5 SHEET 1 OF 3(YeorgeJZafundnk,

gig wfiz i Q g PATENTEBAPR 18 m2 SHEET 3 U? 3 1 FILM CARTRIDGE GUIDEASSEMBLY BACKGROUND OF THE INVENTION This invention relates to a movieprojector of the type which operates a film cartridge and which isintended to be used as a teaching aid in the showing of training films.In the design of this type of movie projector, careful considerationmust be given to the fact that the operator will on many occasions beunskilled and might even be a child. One of the difficult tasksinoperating a movie projector is, of course, the insertion and removalof a film reel. The use of film cartridge has greatly simplified thisoperation, but it is still possible to damage the film if the cartridgeis improperly inserted into the projector.

Accordingly, one object of this invention is to provide a movieprojector housing having a receptacle for receiving a film cartridge,where the receptacle andfilm cartridge housing are constructed withmatingguide surfaces which cooperate to prevent damage to the filmduring the loading and unloading of the film cartridge.

Another object of this invention is to provide'a movie pro jectorhousing having a receptacle for receiving a film cartridge, where thereceptacle and film cartridge housings are constructed with mating guidesurfaces which cause the cartridge to follow a predetermined path wheninserted or removed from the receptacle to thereby smoothly, with aminimum of wear to the film, bring the film cartridge into properoperating relationship with the various operating components of themovie projector.

SUMMARY or THE INVENTION A motion picture projector housing isconstructed with a cartridge receptacle formed on one ofits side walls.Also, this side wall carries the various operating components of theprojector, including a claw drive mechanism and a film feed sprocket.The film picker of the claw drive mechanismand the the film cartridge,the cartridge has to be -inserted endwise,

and once inserted, some holding action is thereby provided for thecartridge. At the forward end of the cartridge receptacle the filmpicker and feed sprocket are located adjacent the margin of thereceptacle opening. At the rearward end of the cartridge receptacle,there is provided a spring-biased lever for urging the firm cartridgeforwardly towards the film picker and feed sprocket.

To install the film cartridge in the cartridge receptacle, its rear endis inserted through the cartridge receptacle opening and pushedrearwardly against the spring-biased lever until the front end'of thefilm cartridge clears the forward end of the receptacle opening. Uponclearing the forward end, the spring-biased lever urges the cartridgeforwardly into operative engagement with the film picker and feedsprocket.

To insure that the film cartridge is correctly and smoothly brought intooperating engagement with the projectors operating components and toavoid scratching v or other damage to the film, the film cartridge andfilm cartridge receptacle have a number of mating guide surfaces thatcause the film cartridge to follow the same path during its insertionand removal. In the exemplary embodiment one set of these guide surfacesis provided by a pair of cam surfaces on the forward end of thecartridge receptacle that cooperates with cam follower surfaces on thefront end of the film cartridge to cause the forward end of thecartridge to swing inwardly as the cartridge is inserted and prevent itsforward motion until the cartridge is in direct alignment with theprojectors operating components.

2 BRIEF DESCRIPTION OF DRAWING There is shown in the accompanyingdrawing, the preferred embodiment of this invention, in which:

FIG. 1 is a side elevational view of a motion picture projector having afilm cartridge receptacle provided on its side wall and a cartridgecontained therein;

FIG. 2 is an enlarged view of the film cartridge receptacle depicted inFIG. 1 with the film cartridge inserted therein;

FIGS. 3, 4 and 5 are top cross sectional views'of the film cartridgereceptacle illustrating various positions of a film cartridge relativeto the receptacle;

FIG. 6 is a cross sectional view taken along the line 6-6 of FIG. 4 andlooking in the direction of the arrows;

FIG. 7 is a front elevational view of a film cartridge having an upperand lower cam follower surfaces;

FIG. 8 is a front elevational view of a part of the film cartridgereceptacle having an upper and lower cam surfaces which mate with thecam surfaces of the film cartridge illustrated in FIG. 7; and

FIG. 9 is a side elevational view of the inside wall of the filmcartridge illustrated in FIG. 7.

DESCRIPTION OF PREFERRED EMBODIMENT For the purposes of illustratingthis invention, the preferred embodiment is illustrated in FIG. 1 as amotion picture projector 10 having a film cartridge receptacle 12 fonnedon the outside surface of one of its side walls 14 for receiving a filmcartridge 16 therein.

Integrally formed and extending perpendicular from the side wall 14 ofmovie projector 10 are two generally parallel walls 18 and two parallelwalls 20 which are perpendicular to walls 18, and are joined together attheir ends to form a rectangular shaped structure 22. Covering the rightend (as viewed in FIG. 1) of the rectangular-shaped structure 22 isacover plate 24, which is held in place by a screw 26 threaded into sidewall 14 (not shown). Across the left hand end of the rectangular shapedstructure 22 is a narrow strip 28 which together with the cover plate 24and the parallel walls 18 define a generally rectangular shaped opening30 for the film cartridge receptacle 12.

The side wall 14 of the motion picture projector 10 also supports thevarious film projecting components of the motion picture projector,including a film picker 32 (FIG. 2) of an interrnittent film drivemechanism (not shown) and a film feed sprocket 34 (FIG. 2), which aredisposed in parallel alignment with the flange 37 of cover plate 24.Also, a sound head could be disposed between the picker 32 and the filmdrive 34 if the motion picture projector 10 were to include soundtransmissron.

The film cartridge 16 has a shallow box-shaped housing or casing 36 inwhich is contained a motion picture film having a spiral row portioncontaining many convolutions wound about a reel and an exhibitionportion consisting of a single strip of film. The manner in which themotion picture film is con tained in the housing 36 and driven by themotion picture projector 10 is not important for the purposes of thisinvention, except the fact that the exhibition portion of the filmpasses along the front wall 38 of the film cartridge housing. Oneexample of the manner in which the film is contained within the filmcartridge housing and cooperates therewith is disclosed in theco-pending patent application of Otto R. Nemeth, U.S. Pat. Ser. No.722,646, entitled Film Handling System, which is assigned to the sameassignee as this invention.

As shown in FIG. 7, there is provided in the front wall 38 of the filmcartridge housing 36, film projection openings including an upperelongated opening 40 for receiving a film picker and a lower opening 44for receiving the film feed sprocket 34 when the film cartridge 16 isinserted in the film cartridge receptacle l2.

From the foregoing description, it will become apparent that upon theinsertion or removal of the film cartridge housing 36, its front wall 38must be moved into and away from the film picker 32'and feed sprocket 34in a straight direction to prevent any damage to the film.

The film cartridge 16 is urged and held in operative engagement with thefilm picker 32 and feed sprocket 34 by a springbiased lever 50 mountedon the inside wall surface of side wall 14 of movie projector 10, and aspring finger 45 mounted on side wall 14 adjacent the forward end ofreceptacle opening 30,- the finger 45 being adapted'to engage onaperture 46 provided in cartridge front wall 38. The spring-biased lever50 is constructed as a one-piece member having a mounting portion 52 anda cartridge engaging portion 54 extending perpendicular from themounting portion 52 through an opening 56 in the side wall 14. Themounting portion 52 is slidably mounted on the inside surface of sidewall 14 by means of two slots 58, 60 formed at opposite ends of themounting portion 52 that cooperate, respectively, with a pair ofmounting studs 62, 64 to guide the cartridge engaging portion 54in agenerally forward direction relative to cartridge receptacle 12. Thecartridge engaging portion 54 is constantly urged towards the ing unduewear to the film. Similarly, as illustrated in FIG. 5, it is impossibleto remove the film cartridge 16 out of the film cartridge receptacle 12and away from theback wall 79 until the outer margin of the cam followersurfaces 74, 76 clear the edge of cam surfaces 70, 72. Consequently,these mating surfaces require that the front wall 38 of film cartridgehousing 36 will always be guided straight into the opening betweenflange 37 and side wall 14.

The upper and lower cam surfaces 70, 72 are identical in shape and as isdepicted in FIGS. 3 5, have a straight portion 71 and a slanting portion73. Likewise, the upper and lower cam follower surfaces 74, 76 areidentical in shape and have a straight portion 75 and a slanting portion78. As the rear end of cartridge 16 is inserted into receptacle 12 (seedotted lines of FIG. 3), the slanting portions 73 of cam surfaces 70, 72are engaged by the inside wall 77 of film cartridge which guide theforward end of cartridge 16 rearwardly. Further inward moveflange 37 ofcover member 24 through the action of a spring 1 66 under tensionstretched betweenmounting stud 64 and hook 68'on the mounting portion52. Turning to the structure for holding the forward end of thecartridge in place, it includes the spring finger 45 having an inclinedtip 45a adapted to ride up onto an inclined toe portion 46a of thecartridge inside wall as the cartridge is biased toward the filmprojecting apparatus. (See FIGS. 3, 4 and 5).

Referring to the latter figures, it can be appreciated that the lengthof the cartridge housing 36 between its front and rear walls 38, 39 issubstantially longer than the length of the opening 30 of receptacle 12between its forward and rearward ends. Thus, it is necessary for theuser to first insert the rear end of cartridge 16 and to push the rearwall 39 of the cartridge 16 against the spring biased lever 50 until thefront wall 38 can swing past the forward 'end of opening 30, at whichtime, the cartridge engaging portion 54 under the urging of spring 66will push the cartridge 16 forwardly into operative engagement with thefilm picker 32, feed sprocket 34, and alsospring finger 45. The latteris operative to hold the car tridge so as to prevent lateral movement ofthat end of the cartridge, once it is installed.

To assist the user in inserting the film cartridge. 16 into thecartridge receptacle 12, the outside wallmember 61 of cartridge housing36 is provided with an upper and lower arcuate recesses 63, 65 that canbe readily grasped by the user, and the parallel horizontalwalls 18 haveupper and lower rectangular cut-outs 67, 69 that overlap the respectivearcuate recesses 63, 65 as the cartridge is inserted into receptacle 12.

As will now be explained, to insure that the film cartridge 16 is alwaysproperly inserted and removed with respect to the receptacle 12 the filmcartridgehousing 36 and film cartridge receptacle 12 have a number ofmating surfaces to guide the film cartridge 16 along a predeterminedpath.

Two of these mating surfaces are provided by upper and lower camsurfaces 70, 72 formed on flange 37 of cover plate 24 which are engagedby upper and lower cam follower surfaces 74, 76, respectively, formedacross the upper and lower edges of the front wall 38 of film cartridgehousing 36. As can be seen by referring to FIGS. 3 and 4 of theexemplary embodiment, the cam follower surfaces 74, 76 ride along therespective cam surfaces 70, 72 as the cartridge 16 is inserted into thereceptacle 12 preventing the front wall 38 of the film p 65 cartridgehousing 36 from moving forwardly until the inside surface 77 ofcartridge housing 36 is adjacent the back wall 79 of cartridgereceptacle 12. As a consequence of this cooperating action between thecam surfaces 70, 72 and the cam follower surfaces 74, 76, it isimpossible for the film cartridge 16 to move forward towards the filmprojecting mechanism or apparatus, 'exemplarily shown as the film picker32 and feed sprocket 34 prior to the front wall 38being suitablyaligned. In the present instance the alignment assures that thecartridge film projection openings and the receptacle film projectingmechanism engage and disengage without damaging or causment of cartridge16 causes slanting portions 78 of cam follower surfaces 74,76 to ridefirst along slanting portions 73 and then along straight portions 71 ofcam surfaces 70, 72, with the result that the front end of cartridge 16swings rearwardly 'andtowards back wall 79. Finally, straight portions75 of cam follower surfaces 74, 76 ride along straight portions 71 ofcam surfaces 70, 72 causing the front end of cartridge 16 to movestraight towards back wall 79 of receptacle 12.

Provided at the upper and lower edges at the outside corners of frontwall 38 (FIG. 2) of the cartridge housing 36, are upper and lowerrecesses 120, 122 which are in the plane of the upper and lower camfollower surfaces 74 and 76, respectively. When the inside wall 77 ofcartridge 16 engages receptacle back wall 79, the upper and lower camsurfaces 70, 72 are in alignment with upper and lower recesses 120, 122,and consequently cartridge 16 is free to move forwardly under thebiasing action of lever 50.

The left end of the outside side wall 61 of film cartridge housing 36 isrecessed at 84. This recess 84 slides along the outer lip 86-(see FIGS.3 5) of narrow strip 28 as the film cartridge 16 is inserted intothefilm cartridge receptacle 12. As illustrated in FIG. 5, the cornerdefined by the rear wall 39 and the outside side wall 61 of filmcartridge housing'36 engages and is guided by a rib 88 extending fromnarrow strip 28 .as the front end of the film cartridge 16 is swungtowards and away from the back wall 79 of the cartridge receptacle 12.

As the cartridge 16 is inserted into receptacle 12, the inside side wallsurface "of film cartridge housing 36 is brought into sliding engagementwith the side wall 14 of the movie projector 10 and then thespring-biased lever 50 urges the film cartridge 16 forwardly towards thecover plate 24. During this forward movement, the cartridge 16 is guidedin a straight path by the cooperating action between a long narrow rib90 formed on the outside surface of back wall 79 and along narrow slot92 (FIG. 9) formed in the inside side wall surface 70 of cartridgehousing 36 having awidth slightly larger than the width of the longnarrow rib 90.

There is also provided upper and lower guide surfaces formed in the filmcartridge receptacle 12 for guiding the upper and lower side walls 102,104 of cartridge housing 36 as the cartridge 16 is moved towards andaway from the film picker 32 and feed sprocket 34, and the guidesurfaces com- 111, 113 of cartridge receptacle 12. As shown in FIG. 6,the

four skids 106, 108, and 112 taper inwardly towards the p outside ofcartridge receptacle 12 so that only the inside edge of the upper andlower wallsl02, 104 of cartridge housing 36 are in sliding engagement toeffectively reduce the friction therebetween.

' 70 The forward movement of film cartridge housing 36 is stopped whenfilm feed sprocket opening 44 engages film feed sprocket projecting boss43 (FIG; 2) emanating from back wall 79 of projector side wall 14 asdepicted in FIG. 2. It is recognized that other fixed appendages mountedon interior 7 surfaces of film cartridge receptacle 12 or cover plate 24opening in back wall 79 from drive shaft 128 could engageother areas offilm cartridge housing 36 to effectively block the forward movement offilm cartridge 16 similarly to the manner depicted. In this stopposition, any lateral movement of the frontwall 38 of film cartridge 16is limited by the abutting relationship between the recess 98 (FIG. 7)formed along the comer of the front wall 38 and the outside side wall 61and the lip 100 (FIG. 5) formed by the intersection of flange 37 andwall 96. The spring finger 45 cooperates with aperture 46 to hold thewall 38 and that end of the cartridge against lateral movement, whichotherwise may be permitted by the tolerances in the fit of parts. I

From the foregoing description, it is apparent that during the loadingand unloading of the cartridge 16, the cartridge housing 36is guidedthrough a predetermined path v(as depicted in the FIG. 3 through 5showings). The rear wall 39 of cartridge housing 36 is first inserted'inthe rearward end of cartridge receptacle 12 and is-engaged by thecartridge engaging portion 54 of spring-biased lever 50. As thecartridge'16 is pushed-furtherinto the receptacle 12, the rear wall 39pushes the cartridge engaging portion 54 rearwardly against the biasingforce of spring 66, and simultaneously front wall38 is swung towards theback wall 79 of receptacle 12 through the guiding action provided byupper and lower cam follower surfaces 74, 76 ridingalong upper and lowercam surfaces 70, 72. During this swinging motion of cartridge 16 towardsback wall 79 of receptacle 12,- the lamp housing (not shown) mounted onthe back wall 79 projects through lamp aperture 126 (FIG; 9) intheinside wall 70 of cartridge housing 36 and a flexible drive member(not shown but extending through an of FIGS. 3-5) projects throughaperture 130 '(FIG. 9) in the inside wall 70 of cartridge housing 36 fordriving the row portion of the film contained in cartridge 16.

Upon the inside wall 70 of cartridge housing 36 being brought intosliding engagement with backwall 79 of receptacle 12, the cartridge 16is free to move forwardly and it does so under the urging ofspring-biased lever 50. During this forward movement, the cartridge 16is guided by the upper and lower skids 106, 108 and 110, 112 and by theelongated rib 92 directly towards the film picker 32 and feed sprocket34. The front wall 38 is prevented from any lateral movement by theinterfit of the receptacle supported spring finger 45 acting against thecartridge rear wall 77 by way of aperture 46.

While the invention has been described in connection with one specificembodiment, it is to be understood that this is by way of illustrationand not byway of limitation. The scope of the invention is definedsolely bythe appended claims which should be constru l claim: I 1. In afilm projecting system including a projector having a d asbroadly'as theprior art will permit.

receptacle formed with an opening adapted to receive a film cartridge,the film cartridge adapted to be received in the cartridge receptaclehaving a plurality of walls defining an enclosure for the film carriedtherein with one wall having an opening permitting operative access foreffecting projection of film contained therein, the film projectingapparatus adapted to mechanically engage the film and beingmountedadjacent the margin of said receptacle opening, and means forbiasing said cartridge into engagement with said film projectingapparatus, the improvement comprising a guide means carried by an insideone of said cartridge receptacle enclosure defining walls and followermeans carried by said film cartridge and complernentarily' shaped tomatingly receive said guide means, said follower means engageable withsaid guide means to permit relative movement between the film and filmprojecting apparatus along a predetermined path at all times that thefilm and film projecting apparatus are brought into engagement and takenout of engagement, the film receptacle access opening having a widthsufircient to receive the cartridge anda length shorter than thecartridge, the latter preventing engagement of the film and filmprojecting apparatus until said guide means and follower means,respectively, are matingly engaged to the projector along saidpredetennined path for operative engagement of the film and theprojecting apparatus.

2. The combination of claim 1, wherein said guide means carried by saidcartridge receptacle comprises a first and second guide means and saidfollower means carried by said film cartridge comprises a first andsecond follower means, where said first follower means cooperates withsaid first guide means to prevent said one wall of said cartridge frommoving into operative engagement with said film projecting apparatusprior to-a predetermined alignment therewith being effected, and wheresaid second follower means cooperates with said second guide means todirect said one wall of said cartridge straight into operativeengagement with said film projecting apparatus as said biasing meansurges said cartridge into engagement with said film projectingapparatus.

3. The combination of claim 2, wherein said first means comprises a pairof cam surfaces extending into said receptaan elongated slot formed inan inside'one of said plurality of said cartridge walls having awidth'adapted to receive said elongated rib and in alignment therewithwhen said cartridge is contained in said receptacle.

5. The combination of claim 1, the improvement further comprising ameans for holding said one end of said cartridge in place upon saidcartridge being brought into engagement with said film projectingapparatus so as to prevent any lateral movement of said one end.

6. The combination of claim 5, .wherein said holding means comprises aspring finger being mounted adjacent said receptacle opening and anaperture formed in said one wall of said cartridge in alignment with thefree end of said spring finger to receive said free end when saidcartridge moves into engagement with said film projecting apparatus,where said free end urges said one end of said cartridge against a wallof said I receptacle.

7. in a motion picture projector having a film cartridge receptacleformed on the outer surface of one wall that supports operativecomponents of the projector, the film cartridge adapted to be receivedin the cartridge receptacle having a plurality of walls defining anenclosure for the film carried therein with a forward one of said wallshaving a film picker opening and a film feed sprocket opening, the filmpicker and film feed sprocket being mounted adjacent the margin of saidfilm receptacle opening at said forward end, and a spring-biased levermounted on said one wall adjacent the margin of said receptacle openingat said rearward end, the improvement comprising guide means carried bysaid cartridge receptacle and follower means carried by said filmcartridge that cooperate with said guide means to prevent said frontwall of said film cartridge from moving into operative engagement withsaid film picker and said feed sprocket prior to a predeterminedalignment therewith being effected.

8. The combination of claim 7, wherein the improvement further-comprisesa second guide means carried by said cartridge receptacle to direct saidforward wall of said film cartridge straight into operative engagementwith said film picker and said feed sprocket as said spring-biased leverurges said film cartridge toward said forward end of said receptacle.

9. The combination of claim 8, wherein said second guide means includesan elongated rib extending from a back wall of 'said cartridgereceptacle in a generally perpendicular so that the cartridge carryingthe film can only travel relative tridge includes an elongated slotformed in an inside one of said plurality of cartridge walls having awidth adapted to receive said elongated rib and in alignment therewithwhen said cartridge is'contained in said receptacle.

10. The combination of claim 7, wherein said guide means comprises upperand lower cam surfaces formed at said forward. end of said cartridgereceptacle and extending into said receptacle opening and wherein saidfollower means comprises upper and lower cam follower surfaces formed insaid film cartridge and adapted to ride along said upper and lower camsurfaces to guide said forward wall so as to prevent sliding contactbetween said film and said receptacle as said cartridge is inserted andis pushed against the biasing force of said spring-biased lever.

11. The combination of claim 7, wherein the improvement furthercomprises a means for holding said one end of said cartridge in placeupon said cartridge being brought into engagement with said filmprojecting apparatus so as to prevent any lateral movement of said oneend.

12. The combination of claim 1 1, wherein said holding means comprises aspring finger being mounted adjacent said receptacle opening and anaperture fonned in said one wall of said cartridge in alignment with thefree end of said spring finger to receive said free end when saidcartridge moves into engagement with said film projecting'apparatus,where said free end urges said one end of said cartridge against a wallof said receptacle.

1. In a film projecting system including a projector having a receptacleformed with an opening adapted to receive a film cartridge, the filmcartridge adapted to be received in the cartridge receptacle having aplurality of walls defining an enclosure for the film carried thereinwith one wall having an opening permitting operative access foreffecting projection of film contained therein, the film projectingapparatus adapted to mechanically engage the film and being mountedadjacent the margin of said receptacle opening, and means for biasingsaid cartridge into engagement with said film projecting apparatus, theimprovement comprising a guide means carried by an inside one of saidcartridge receptacle enclosure defining walls and follower means carriedby said film cartridge and complementarily shaped to matingly receivesaid guide means, said follower means engageable with said guide meansto permit relative movement between the film and film projectingapparatus along a predetermined path at all times that the film and filmprojecting apparatus are brought into engagement and taken out ofengagement, the film receptacle access opening having a width sufficientto receive the cartridge and a length shorter than the cartridge, thelatter preventing engagement of the film and film projecting apparatusuntil said guide means and follower means, respectively, are matinglyengaged so that the cartridge carrying the film can only travel relativeto the projector along said predetermined path for operative engagementof the film and the projecting apparatus.
 2. The combination of claim 1,wherein said guide means carried by said cartridge receptacle comprisesa first and second guide means and said follower means carried by saidfilm cartridge comprises a first and second follower means, where saidfirst follower means cooperates with said first guide means to preventsaid one wall of said cartridge from moving into operative engagementwith said film projecting apparatus prior to a predetermined alignmenttherewith being effected, and where said second follower meanscooperates with said second guide means to direct said one wall of saidcartridge straight into operative engagement with said film projectingapparatus as said biasing means urges said cartridge into engagementwith said film projecting apparatus.
 3. The combination of claim 2,wherein said first means comprises a pair of cam surfaces extending intosaid receptacle opening and wherein said first follower means comprisesa pair of cam follower surfaces formed in said film cartridge andadapted to ride along said pair of cam surfaces to guide said one wallso as to prevent sliding contact between said film and said receptacleas said cartridge is inserted and is pushed against said biasing means.4. The combination of claim 2, wherein said second guide means includesan elongated rib extending from one of the walls of said cartridge in astraight direction towards said film projecting apparatus and saidsecond follower means includes an elongated slot formed in an inside oneof said plurality of said cartridge walls having a width adapted toreceive said elongated rib and in alignment therewith when saidcartridge is contained in said receptacle.
 5. The combination of claim1, the improvement further comprising a means for holding said one endof said cartridge in place upon said cartridge being brought intoengagement with said film projecting apparatus so as to preVent anylateral movement of said one end.
 6. The combination of claim 5, whereinsaid holding means comprises a spring finger being mounted adjacent saidreceptacle opening and an aperture formed in said one wall of saidcartridge in alignment with the free end of said spring finger toreceive said free end when said cartridge moves into engagement withsaid film projecting apparatus, where said free end urges said one endof said cartridge against a wall of said receptacle.
 7. In a motionpicture projector having a film cartridge receptacle formed on the outersurface of one wall that supports operative components of the projector,the film cartridge adapted to be received in the cartridge receptaclehaving a plurality of walls defining an enclosure for the film carriedtherein with a forward one of said walls having a film picker openingand a film feed sprocket opening, the film picker and film feed sprocketbeing mounted adjacent the margin of said film receptacle opening atsaid forward end, and a spring-biased lever mounted on said one walladjacent the margin of said receptacle opening at said rearward end, theimprovement comprising guide means carried by said cartridge receptacleand follower means carried by said film cartridge that cooperate withsaid guide means to prevent said front wall of said film cartridge frommoving into operative engagement with said film picker and said feedsprocket prior to a predetermined alignment therewith being effected. 8.The combination of claim 7, wherein the improvement further comprises asecond guide means carried by said cartridge receptacle to direct saidforward wall of said film cartridge straight into operative engagementwith said film picker and said feed sprocket as said spring-biased leverurges said film cartridge toward said forward end of said receptacle. 9.The combination of claim 8, wherein said second guide means includes anelongated rib extending from a back wall of said cartridge receptacle ina generally perpendicular direction to an imaginary line connecting saidfilm picker and said feed sprocket and wherein said inside wall of saidcartridge includes an elongated slot formed in an inside one of saidplurality of cartridge walls having a width adapted to receive saidelongated rib and in alignment therewith when said cartridge iscontained in said receptacle.
 10. The combination of claim 7, whereinsaid guide means comprises upper and lower cam surfaces formed at saidforward end of said cartridge receptacle and extending into saidreceptacle opening and wherein said follower means comprises upper andlower cam follower surfaces formed in said film cartridge and adapted toride along said upper and lower cam surfaces to guide said forward wallso as to prevent sliding contact between said film and said receptacleas said cartridge is inserted and is pushed against the biasing force ofsaid spring-biased lever.
 11. The combination of claim 7, wherein theimprovement further comprises a means for holding said one end of saidcartridge in place upon said cartridge being brought into engagementwith said film projecting apparatus so as to prevent any lateralmovement of said one end.
 12. The combination of claim 11, wherein saidholding means comprises a spring finger being mounted adjacent saidreceptacle opening and an aperture formed in said one wall of saidcartridge in alignment with the free end of said spring finger toreceive said free end when said cartridge moves into engagement withsaid film projecting apparatus, where said free end urges said one endof said cartridge against a wall of said receptacle.